RESUMO
With increasing demand of the public toward antimicrobial textiles, there should be the proper fabrication of such types of clothes, and it is possible with biogenically synthesized metal nanoparticles (NPs). It is necessary to find cheap and eco-friendly resources for such synthesis. In this work, we used Polygonum microcephalum from Assam, India, to synthesize copper and silver (Ag) NPs. As far as we know, this is the first report on the synthesis of AgNPs and copper oxide NPs (CuONPs) from P. microcephalum The synthesis was done from the aqueous leaf extract. The AgNPs and CuONPs formation was observed by the change in the color of the solution and was confirmed by UV-visible spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. Characterization of NPs was done with various physicochemical characterization techniques. The synthesized spherical-shaped AgNPs were found to be effective against the representative bacteria, Gram +ve (Staphylococcus Aureus) and Gram -ve (Escherichia Coli and Pseudomonas Aeruginosa), but the flake-shaped CuONPs were not effective due to their bigger size (>200 nm). The results clearly show that the AgNPs used in this study were toxic against three pathogens. The minimum inhibitory concentrations of AgNPs for S. aureus and E. coli were 32 µg/mL. The uptake analysis of AgNPs for both pathogens demonstrates the mechanism of toxic effects. The present study confirms that P. microcephalum leaf extract is effective in AgNP synthesis, and it could be a cost-effective and environmentally friendly resource for the green synthesis of AgNPs.
RESUMO
Nowadays polymer-based thin film nanocomposite (TFN) membrane technologies are showing key interest to improve the separation properties. TFN membranes are well known in diverse fields but developing highly improved TFN membranes for the removal of low concentration solutions is the main challenge for the researchers. Application of functional nanomaterials, incorporated in TFN membranes provides better performance as permeance and selectivity. The polymer membrane-based separation process plays an important role in the chemical industry for the isolation of products and recovery of different important types of reactants. Due to the reduction in investment, less operating costs and safety issues membrane methods are mainly used for the separation process. Membranes do good separation of dyes and ions, yet their separation efficiency is challenged when the impurity is in low concentration. Herewith, we have developed, UiO-66-NH2 incorporated TFN membranes through interfacial polymerization between piperazine (PIP) and trimesoyl chloride (TMC) for separating malachite green dye and phosphate from water in their low concentration. A comparative study between thin-film composite (TFC) and TFN has been carried out to comprehend the benefit of loading nanoparticles. To provide mechanical strength to the polyamide layer ultra-porous polysulfone support was made through phase inversion. As a result, outstanding separation values of malachite green (MG) 91.90 ± 3% rejection with 13.32 ± 0.6 Lm-2h-1 flux and phosphate 78.36 ± 3% rejection with 22.22 ± 1.1 Lm-2h-1 flux by TFN membrane were obtained. The antifouling tendency of the membranes was examined by using bovine serum albumin (BSA)-mixed feed and deionized water, the study showed a good ~84% antifouling tendency of TFN membrane with a small ~14% irreversible fouling. Membrane's antibacterial test against E. coli. and S. aureus. also revealed that the TFN membrane possesses antibacterial activity as well. We believe that the present work is an approach to obtaining good results from the membranes under tricky conditions.
